Improvement in dies for cutting screw-threads



' JOHN J GRANT.

, Improvement in Dies for Cutting Screw Threads.

No. 120,266 Patentd our 24 1371.

PATENT OEEIoE.

JOHN J. GRANT, OF GEEEEEIELD, MAssAcHUsETTs.

IMPROVEMENT IN DIES FOR CUTTING SCREW-THREADS.

Specification forming part of Letters Patent No. 120,266, dated October24, 1871.

To all whom it may concern.-

Be it known that I, JOHN J. GRANT, of Greenfield, in the county ofFranklin and State of Massachusetts, have invented a new and usefulImprovement in Dies for Cutting Screw-Threads; and 1 do hereby declarethat the following is a full, clear, and exact description thereof,reference being had to the accompanying drawing forming part of thisspecification.

This invention consists in the arrangement within the diestock orholder, and between the dies, of taper or taper-headed adjusting-screwsfor setting out the dies, such screws operating, in combination withexternal set-screws, to obtain a perfect and secure adjustment of thedies.

In the accompanying drawing, Figure 1 is a plan of the die. Fig. 2 is atransverse section of the same taken at the dotted line 00 w in Fig. 1and Fig. 3 is another transverse section taken at the line 3 y in Fig.1.

Similar letters of reference indicate correspond in g parts in all thefigures.

A is the die-stock or holder, which is of rectangular form, having inthe middle of its outer side a cavity, a, represented of circular form,for the reception of the dies B B. In the bottom of said recess is ahole,b, that extends right through the stock to permit the passage ofthe cut screw from the die. The dies B B are of a size and formexternally to fit easily into the cavity a, and except for the recessesc 0 provided on their opposite or adjacent faces at the sides of thecutting portions 01 d for the reception of the taper or conical-headedscrews 0 0, they are or may be like the dies in common use for cuttingscrewthreads. The screws (J (J have their outer portions or heads madetaper in an inward direction, and they fit within the recesses c c inthe dies B B, which are of corresponding form, and screw on the stock A.D D are the screws that form the external adjustment. They screw intothe sides of the stock A and bear against the middle portions of theexterior or circular portion of the dies B B.

To adjust the dies to enable screws of different depths or sizes to becut, the conical-headed screws 0 O are screwed either further into thestock to separate the dies, or from the stock to allow the set-screws DD to force them toward each other. The set-screws D D are screwed up tohold the dies in any position to which they are adjusted by the screws 00.

What is claimed and desired to be secured by Letters Patent is- Thecombination, with the stock and dies and the set-screws or equivalentexternal adjustment of the dies, of the interposed taper or taperheadedscrews, applied to operate substantially as herein specified.

JOHN J. GRANT.

FRED. HAYNES. (14)

